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Abstract Background To date, at least 746 genes have been identified to cause intellectual disability (ID). Among them, mutations in the Methyl CpG binding protein 2 (MECP2) gene are the leading cause of Rett syndrome and associated ID. Methods Considering the large number of ID-associated genes, we applied trio-based whole-exome sequencing (trio-WES) and in silico analysis for genetic diagnosis of 294 children with ID. Results Three de novo heterozygous mutations [NM_004992.3: c.502C > T, p.(Arg168*), c.916C > T, p.(Arg306Cys), and c.879C > G, p.(Ile293Met)] in MECP2 were identified in three unrelated girls. The first two mutations were detected in two patients who were diagnosed as typical Rett syndrome, X-linked ID and psychomotor retardation. The third mutation (c.879C > G), a previously unreported, was found in a 6-year-old girl with ID, microcephaly, severe underweight and psychomotor retardation. Particularly, this extremely rare de novo mutation (DNM) is located in the transcriptional repression domain (TRD) of MECP2, where at least 62 different causal mutations are identified. Conclusions We identified three DNMs in MECP2 in a cohort of 294 individuals with ID. The novel c.879C > G mutation, as a likely pathogenic allele, may become a risk factor associated with X-linked ID, microcephaly and psychomotor retardation.

Abstract Background Intellectual disability (ID) constitutes the most common group of neurodevelopmental disorders. Exome sequencing has enabled the discovery of genetic mutations responsible for a wide range of ID disorders. Case presentation In this study, we reported on two male siblings, aged 4 and 2 years, with motor and mental developmental delays and mild dysmorphic facial features. To identify the genetic causes of these symptoms, we employed trio-whole exome sequencing for the proband. We found a novel hemizygous missense variant in the PAK3 gene (c.1112G > A, p.Cys371Tyr), which encodes the p21-activated kinase 3, in the proband, which inherited from mother. The younger brother also has the hemizygous variant, which was confirmed by Sanger sequencing. The variant is located in the kinase domain and was regarded as a likely pathogenic variant in this family. Conclusion We diagnosed two male siblings with developmental delays as having a PAK3 likely pathogenic variant. This finding expands the list of PAK3 gene mutations associated with neurodevelopmental disorders and provides further details on its clinical features.

The proper connection between the pre- and post-synaptic nervous cells depends on any element constituting the synapse: the pre- and post-synaptic membranes, the synaptic cleft, and the surrounding glial cells and extracellular matrix. An alteration of the mechanisms regulating the physiological synergy among these synaptic components is defined as “synaptopathy.” Mutations in the genes encoding for proteins involved in neuronal transmission are associated with several neuropsychiatric disorders, but only some of them are associated with Developmental and Epileptic Encephalopathies (DEEs). These conditions include a heterogeneous group of epilepsy syndromes associated with cognitive disturbances/intellectual disability, autistic features, and movement disorders. This review aims to elucidate the pathogenesis of these conditions, focusing on mechanisms affecting the neuronal pre-synaptic terminal and its role in the onset of DEEs, including potential therapeutic approaches.

Background: Home care for children with severe motor and intellectual disabilities (SMID) is challenging for parents because it is highly intensive and long-lasting. The pursuit of happiness is an essential goal for everyone. However, only a few studies have focused on the happiness of families with such children., Objective: The study aimed to examine the subjective happiness of parents of children with SMID receiving home care and identify the factors associated with their happiness., Methods: We conducted a cross-sectional online questionnaire-based survey of 23 parents of children with SMID and nurses with children without disabilities as controls at Tottori University Hospital, Yonago, Japan from July 1 to August 31, 2023. We set the subjective happiness scale (SHS) scores as the outcomes. We used the Mann-Whitney U test to compare the SHS scores between the two groups. Moreover, we extracted the clinical and demographic factors affecting the SHS scores of parents of children with SMID using univariate linear regression analysis., Results: We obtained responses from 12 parents with SMID and 105 controls. The average SHS scores of parents with SMID and controls were 4.8 and 4.7, respectively, and both groups did not differ significantly. Univariate analysis showed that parental male sex and the presence of a tracheostomy were negatively associated with the SHS scores of parents., Conclusions: The SHS scores did not differ significantly between parents with SMID and controls. However, more attention seemed necessary for fathers and parents of children who have undergone tracheostomies. Given the exploratory nature of this study and its small sample size, larger-scale investigations are warranted. Additionally, qualitative research conducted after establishing trustful relationships could provide further insights., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Institutional Ethics Committee of the Tottori University Hospital issued approval 23A025. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Arai et al.)

Background: Long‐term use of antiseizure drugs is associated with a low bone mineral density (BMD) and an increased fracture risk. The literature regarding institutionalised children on chronic antiseizure drugs is limited. Therefore, the aim of this cross‐sectional study is to evaluate the prevalence of low BMD and the history of fractures in institutionalised children with epilepsy and intellectual disability (ID). Methods: A dual‐energy X‐ray absorptiometry of lumbar spine (L1–L4) and hip was performed in 24 children, residing in a long‐stay care facility in the Netherlands. Additionally, serum concentrations of albumin, calcium and 25‐hydroxyvitamin D were determined. Data on fractures were retrospectively extracted from the medical files. Results: Ages of the children (14 male and 10 female) ranged from 5 to 17 years with a mean age of 13.0 (±3.2). The criteria of the International Society for Clinical Densitometry (ISCD) were used for classification of bone mineral disorders. Eight (33.3%) children had a normal BMD (Z‐score > − 2.0). Of the 16 children with a low BMD (Z‐score ≤ − 2.0), three were diagnosed as osteoporotic, based on their fracture history. Ten children (41.7%) were reported to have at least one fracture in their medical history. Serum concentrations of albumin‐corrected calcium (2.28–2.50 mmol/L) and (supplemented) vitamin D (16–137 nmol/L) were within the normal range. Conclusions: This study demonstrated that 67% of institutionalised children with epilepsy and ID had low BMD and 42% had a history of at least one fracture, despite supplementation of calcium and vitamin D in accordance with the Dutch guidelines. [ABSTRACT FROM AUTHOR]

Objective: Intellectual disability (ID) is one of the most common developmental disabilities. To identify the genetic etiology of IDs in Chongqing, we conducted a multistage study in Chinese Han patients.Methods: We collected the clinical and etiological data of 1665 ID patients, including 1,604 from the disabled children evaluation center and 61 from the pediatric rehabilitation unit. Routine genetic screening results were obtained, including karyotype and candidate gene analysis. Then 105 idiopathic cases with syndromic and severe ID/developmental delay (DD) were selected and tested by chromosomal microarray (CMA) and whole exome sequencing (WES) sequentially. The pathogenicity of the CNVs and SNVs were evaluated according to ACMG guidelines.Results: Molecular diagnosis was made by routine genetic screening in 216 patients, including 196 chromosomal syndromes. Among the 105 idiopathic patients, 49 patients with pathogenic/likely pathogenic CNVs and 21 patients with VUS were identified by CMA. Twenty-six pathogenic CNVs underlying well-known syndromic cases, such as Williams-Beuren syndrome, were confirmed by multiplex ligation-dependent probe amplification (MLPA). Nine novel mutations were identified by WES in thirty-fix CNV-negative ID cases.Conclusions: The study illustrated the genetic aberrations distribution of a large ID cohort in Chongqing. Compared with conventional or single methods, a tiered high-throughput diagnostic strategy was developed to greatly improve the diagnostic yields and extend the variation spectrum for idiopathic syndromic ID cases.

Objective: Intellectual disability (ID) is one of the most common developmental disabilities. To identify the genetic etiology of IDs in Chongqing, we conducted a multistage study in Chinese Han patients. Methods: We collected the clinical and etiological data of 1665 ID patients, including 1,604 from the disabled children evaluation center and 61 from the pediatric rehabilitation unit. Routine genetic screening results were obtained, including karyotype and candidate gene analysis. Then 105 idiopathic cases with syndromic and severe ID/developmental delay (DD) were selected and tested by chromosomal microarray (CMA) and whole exome sequencing (WES) sequentially. The pathogenicity of the CNVs and SNVs were evaluated according to ACMG guidelines. Results: Molecular diagnosis was made by routine genetic screening in 216 patients, including 196 chromosomal syndromes. Among the 105 idiopathic patients, 49 patients with pathogenic/likely pathogenic CNVs and 21 patients with VUS were identified by CMA. Twenty-six pathogenic CNVs underlying well-known syndromic cases, such as Williams-Beuren syndrome, were confirmed by multiplex ligation-dependent probe amplification (MLPA). Nine novel mutations were identified by WES in thirty-fix CNV-negative ID cases. Conclusions: The study illustrated the genetic aberrations distribution of a large ID cohort in Chongqing. Compared with conventional or single methods, a tiered high-throughput diagnostic strategy was developed to greatly improve the diagnostic yields and extend the variation spectrum for idiopathic syndromic ID cases. [ABSTRACT FROM AUTHOR]

T-type calcium channels (Cav3.1 to Cav3.3) regulate low-threshold calcium spikes, burst firing and rhythmic oscillations of neurons and are involved in sensory processing, sleep, and hormone and neurotransmitter release. Here, we examined four heterozygous missense variants in CACNA1I, encoding the Cav3.3 channel, in patients with variable neurodevelopmental phenotypes. The p.(Ile860Met) variant, affecting a residue in the putative channel gate at the cytoplasmic end of the IIS6 segment, was identified in three family members with variable cognitive impairment. The de novo p.(Ile860Asn) variant, changing the same amino acid residue, was detected in a patient with severe developmental delay and seizures. In two additional individuals with global developmental delay, hypotonia, and epilepsy, the variants p.(Ile1306Thr) and p.(Met1425Ile), substituting residues at the cytoplasmic ends of IIIS5 and IIIS6, respectively, were found. Because structure modelling indicated that the amino acid substitutions differentially affect the mobility of the channel gate, we analysed possible effects on Cav3.3 channel function using patch-clamp analysis in HEK293T cells. The mutations resulted in slowed kinetics of current activation, inactivation, and deactivation, and in hyperpolarizing shifts of the voltage-dependence of activation and inactivation, with Cav3.3-I860N showing the strongest and Cav3.3-I860M the weakest effect. Structure modelling suggests that by introducing stabilizing hydrogen bonds the mutations slow the kinetics of the channel gate and cause the gain-of-function effect in Cav3.3 channels. The gating defects left-shifted and increased the window currents, resulting in increased calcium influx during repetitive action potentials and even at resting membrane potentials. Thus, calcium toxicity in neurons expressing the Cav3.3 variants is one likely cause of the neurodevelopmental phenotype. Computer modelling of thalamic reticular nuclei neurons indicated that the altered gating properties of the Cav3.3 disease variants lower the threshold and increase the duration and frequency of action potential firing. Expressing the Cav3.3-I860N/M mutants in mouse chromaffin cells shifted the mode of firing from low-threshold spikes and rebound burst firing with wild-type Cav3.3 to slow oscillations with Cav3.3-I860N and an intermediate firing mode with Cav3.3-I860M, respectively. Such neuronal hyper-excitability could explain seizures in the patient with the p.(Ile860Asn) mutation. Thus, our study implicates CACNA1I gain-of-function mutations in neurodevelopmental disorders, with a phenotypic spectrum ranging from borderline intellectual functioning to a severe neurodevelopmental disorder with epilepsy. [ABSTRACT FROM AUTHOR]

Abstract Background PHF21A has been associated with intellectual disability and craniofacial anomalies based on its deletion in the Potocki-Shaffer syndrome region at 11p11.2 and its disruption in three patients with balanced translocations. In addition, three patients with de novo truncating mutations in PHF21A were reported recently. Here, we analyze genomic data from seven unrelated individuals with mutations in PHF21A and provide detailed clinical descriptions, further expanding the phenotype associated with PHF21A haploinsufficiency. Methods Diagnostic trio whole exome sequencing, Sanger sequencing, use of GeneMatcher, targeted gene panel sequencing, and MiSeq sequencing techniques were used to identify and confirm variants. RT-qPCR was used to measure the normal expression pattern of PHF21A in multiple human tissues including 13 different brain tissues. Protein-DNA modeling was performed to substantiate the pathogenicity of the missense mutation. Results We have identified seven heterozygous coding mutations, among which six are de novo (not maternal in one). Mutations include four frameshifts, one nonsense mutation in two patients, and one heterozygous missense mutation in the AT Hook domain, predicted to be deleterious and likely to cause loss of PHF21A function. We also found a new C-terminal domain composed of an intrinsically disordered region. This domain is truncated in six patients and thus likely to play an important role in the function of PHF21A, suggesting that haploinsufficiency is the likely underlying mechanism in the phenotype of seven patients. Our results extend the phenotypic spectrum of PHF21A mutations by adding autism spectrum disorder, epilepsy, hypotonia, and neurobehavioral problems. Furthermore, PHF21A is highly expressed in the human fetal brain, which is consistent with the neurodevelopmental phenotype. Conclusion Deleterious nonsense, frameshift, and missense mutations disrupting the AT Hook domain and/or an intrinsically disordered region in PHF21A were found to be associated with autism spectrum disorder, epilepsy, hypotonia, neurobehavioral problems, tapering fingers, clinodactyly, and syndactyly, in addition to intellectual disability and craniofacial anomalies. This suggests that PHF21A is involved in autism spectrum disorder and intellectual disability, and its haploinsufficiency causes a diverse neurological phenotype.

Abstract Background Balanced structural variants are mostly described in disease with gene disruption or subtle rearrangement at breakpoints. Case presentation Here we report a patient with mild intellectual deficiency who carries a de novo balanced translocation t(3;5). Breakpoints were fully explored by microarray, Array Painting and Sanger sequencing. No gene disruption was found but the chromosome 5 breakpoint was localized 228-kb upstream of the MEF2C gene. The predicted Topologically Associated Domains analysis shows that it contains only the MEF2C gene and a long non-coding RNA LINC01226. RNA studies looking for MEF2C gene expression revealed an overexpression of MEF2C in the lymphoblastoid cell line of the patient. Conclusions Pathogenicity of MEF2C overexpression is still unclear as only four patients with mild intellectual deficiency carrying 5q14.3 microduplications containing MEF2C are described in the literature. The microduplications in these individuals also contain other genes expressed in the brain. The patient presented the same phenotype as 5q14.3 microduplication patients. We report the first case of a balanced translocation leading to an overexpression of MEF2C similar to a functional duplication.

Koolen‐de Vries syndrome (KdVS, MIM#610443) is a rare malformation condition mainly characterized by cognitive impairment in association with craniofacial and visceral anomalies. The core phenotype is caused by mutations in the chromatin remodeler KANSL1 (MSL1V1, KIAA1267, KAT8 Regulatory NSL Complex Subunit 1, MIM#612452), which maps to 17q21.31 critical genomic region (Koolen et al., Nature Genetics 2012;44:639–641). Considering its molecular basis, KdVS is included in the group of Developmental Disorders of Chromatin Remodeling (DDCRs), also termed chromatinopathies. We describe the first KdVS patient of Southern India ethnicity, harboring the typical de novo 17q21.31 microdeletion, including KANSL1. Observed facial features and congenital anomalies are in line with the already reported KdVS phenotype, suggesting that phenotypic features are consistent across different ethnicities. [ABSTRACT FROM AUTHOR]

Background: The current lack of knowledge about intellectual disability (ID) in forensic psychiatric contexts can compromise the legal certainty of these individuals during the medico-legal process. To address ambiguous results in previous literature, the aim of the current study was to estimate the prevalence of ID in a pre-trial forensic psychiatric settings. Moreover, as little is known about the characteristics of offenders with ID, we conducted a clinical characterization of individuals with and without ID being subject to forensic psychiatric assessment.Methods: Using data from several Swedish national registers, we conducted a population-based retrospective observational study on 8,442 individuals being subject to pre-trial forensic psychiatric assessments in Sweden in 1997–2013. We performed univariate analyses to compare the characteristics of individuals with (n = 537) and without ID (n = 7,905).Results: The prevalence of ID was 6.4% in the Swedish pre-trial forensic psychiatric context during the observational period. Compared with individuals without ID, individuals with ID were younger at the time of assessment, had a lower educational level, and had less frequently started families. ID was associated with lower frequency of diagnosed psychotic and bipolar disorders. However, a similar prescription rate of antipsychotics, and a comparable rate of previous inpatient care was observed among individuals with and without ID. Individuals with ID had more often been prescribed anti-libidinal treatments often used for treating sexual disorders, although did not present a higher prevalence of sexual disorder.Conclusions: The prevalence of ID among pre-trial individuals being subject to forensic psychiatric assessment was more than twice as high as assumed in the general population. Our results suggest that individuals with ID received pharmacotherapy without clear indication. Remaining challenges in the clinical management of individuals with ID were indicated by the discrepancy between the occurrence of psychiatric diagnoses, pharmacological treatment patterns, and rates of inpatient care.

Introduction: Mutations in the contactin-associated protein-like 2 (CNTNAP2) gene (MIM#604569) encoding for CASPR2, a cell adhesion protein of the neurexin family, are known to be associated with autism, intellectual disability, and other neuropsychiatric disorders. A set of intronic deletions of CNTNAP2 gene has also been suggested to have a causative role in individuals with a wide phenotypic spectrum, including Pitt-Hopkins syndrome, cortical dysplasia–focal epilepsy syndrome, Tourette syndrome, language dysfunction, and abnormal behavioral manifestations.Case presentation: A 10-years-old boy was referred to the hospital with mild intellectual disability and language impairment. Moreover, the child exhibited minor facial features, epileptic seizures, and notable behavioral abnormalities including impulsivity, aggressivity, and hyperactivity suggestive of the diagnosis of disruptive, impulse-control and conduct disorder (CD). Array comparative genomic hybridization (CGH) revealed a copy number variant (CNV) deletion in the first intron of CNTNAP2 gene inherited from a healthy father.Conclusions: A comprehensive description of the phenotypic features of the child is provided, revealing a distinct and remarkable alteration of social behavior not previously reported in individuals affected by disorders related to CNTNAP2 gene disruptions. A possible causative link between the deletion of a non-coding regulatory region and the symptoms presented by the boy has been advanced.

Background: Children with autism spectrum disorder (ASD) and intellectual disability (ID) are an understudied population whose school inclusion is challenging. Methods: We assessed the effects of “Developmental and Sequenced one-to-one Educational Intervention” (DS1-EI), a ten-hour-per-week adapted instruction programme for five- to nine-year-old children with ASD and ID treated in outpatient health care institutions. A single-blind multisite randomized controlled trial was conducted to compare DS1-EI given for three years with treatment as usual (TAU)(trial registration numbers: ANSM130282B-31 (April 16, 2013) and ACTRN12616000592448). The primary outcome was the change in the psycho-educational profile (PEP). Secondary variables included the Childhood Autism Rating Scale (CARS), Autism Diagnostic Interview-Revised (ADI-R), Vineland Adaptive Behaviour Scale-II (VABS-II), Children's Global Assessment Scale (CGAS) and annual assessment of educational achievement. Statistical analyses used linear mixed models. Findings: Seventy-two participants with severe ASD and ID were recruited. Intention-to-treat and per-protocol analyses showed no significant group*time interaction for the PEP, CARS, ADI-R, VABS-II and CGAS but a significant effect for educational achievement with a better improvement in the DS1-EI group. At the 36-month time point, more DS1-EI children were included in mainstream classrooms. Additional analyses using multivariate models taking into account moderating variables at the baseline (e.g., Developmental Quotient) confirmed that DS1-EI had a significant effect on educational outcomes. Interpretation: DS1-EI did not improve communication or social skills in children with ASD and ID compared with TAU. However, DS1-EI enhanced school skills in four domains (language, mathematics, inter modality, and school autonomy) favouring inclusion in mainstream classrooms more than TAU. Providing such adapted instruction is feasible and should be encouraged. Funding: CNSA; Fondation Bettencourt-Schueller; Fondation EDF

Background: The current lack of knowledge about intellectual disability (ID) in forensic psychiatric contexts can compromise the legal certainty of these individuals during the medico-legal process. To address ambiguous results in previous literature, the aim of the current study was to estimate the prevalence of ID in a pre-trial forensic psychiatric settings. Moreover, as little is known about the characteristics of offenders with ID, we conducted a clinical characterization of individuals with and without ID being subject to forensic psychiatric assessment. Methods: Using data from several Swedish national registers, we conducted a population-based retrospective observational study on 8,442 individuals being subject to pre-trial forensic psychiatric assessments in Sweden in 1997–2013. We performed univariate analyses to compare the characteristics of individuals with (n = 537) and without ID (n = 7,905). Results: The prevalence of ID was 6.4% in the Swedish pre-trial forensic psychiatric context during the observational period. Compared with individuals without ID, individuals with ID were younger at the time of assessment, had a lower educational level, and had less frequently started families. ID was associated with lower frequency of diagnosed psychotic and bipolar disorders. However, a similar prescription rate of antipsychotics, and a comparable rate of previous inpatient care was observed among individuals with and without ID. Individuals with ID had more often been prescribed anti-libidinal treatments often used for treating sexual disorders, although did not present a higher prevalence of sexual disorder. Conclusions: The prevalence of ID among pre-trial individuals being subject to forensic psychiatric assessment was more than twice as high as assumed in the general population. Our results suggest that individuals with ID received pharmacotherapy without clear indication. Remaining challenges in the clinical management of individuals with ID were indicated by the discrepancy between the occurrence of psychiatric diagnoses, pharmacological treatment patterns, and rates of inpatient care. [ABSTRACT FROM AUTHOR]

Adults who are homeless experience high rates of health conditions and psychological distress, including low IQ and functional status. Resources are available to help these individuals, but provision of support is often contingent upon the identification of a known disability. In this context, we examined case managers' (CMs') subjective estimates of IQ and functional status in 77 adult residents of an urban homeless shelter. Participants completed objective measures of IQ and functional capacity. CMs overestimated IQs of lower IQ (IQ < 90) participants, correctly estimated IQs of average IQ (IQ = 90-110) participants, and underestimated IQs of higher IQ (IQ > 110) participants. CMs correctly identified 2 out of 8 participants meeting criteria for intellectual disability and 4 out of 16 participants with impaired functional status. These findings suggest that subjective evaluations of IQ and functional status are prone to a central tendency bias, leading CMs to overlook clients who are in need of assistance. Consequently, the objective measurement of IQ and functional status in homeless shelters is highly recommended. (PsycInfo Database Record (c) 2020 APA, all rights reserved). [ABSTRACT FROM AUTHOR]

Assistive technologies (ATs) aimed at improving the life quality of persons with Autism Spectrum Disorder and/or Intellectual Disability (ASD/ID) is an important research area. Few have examined how this population use and experience AT or their vision for future uses of AT. The present study aimed to update and extend previous research and provides insight from caregivers, and other stakeholders (n = 96), living in Ireland and the United Kingdom, on their experiences of assistive technology (AT) for ASD/ID. Caregiver and professional responses to an anonymous online survey showed that focus individuals were rated low in terms of independent and self-management skills, with scheduling and planning and communication identified as desirable future AT functions. Overall, positive experiences of AT were reported, with AT use more than doubling in recent years. [ABSTRACT FROM AUTHOR]

Speech signals convey speaker's neurodevelopmental state along with phonological information. Recognize a speech disorder by analyzing the speech is essential for human–machine interaction. To develop a subject independent speech recognition system for neurodevelopmental disorders, by identifying voice features from MATLAB toolbox, spectral characteristics and feature selection algorithms are proposed in this paper. Feature selection is applied to overcome the challenges of dimensionality in various applications. This work presents a novel particle swarm optimization (PSO) based algorithm for feature selection. The experiments were conducted using a speech database of the children with intellectual disability with age-matched typically developed and validate the reliability using 10-fold cross-validation technique. The database consists of 141 speech features extracted from linear predictive coding (LPC) based cepstral parameters and Mel-frequency cepstral coefficients (MFCC). Three classification models were applied and obtained the recognition accuracies 90.30% with ANN, 98.00% with SVM and 91.00% with random forest with PSO feature selection algorithm. The results strongly prove the usefulness of the proposed multivariate feature selection algorithm when compared with filter approach. [ABSTRACT FROM AUTHOR]

Objectives: Inborn errors of metabolism (IEMs) are rare genetic disorders. Generally, IEMs are untreatable; however, some IEMs causing intellectual disability are potentially treatable if diagnosed earlier. In this study, levels of some clinically important biochemical parameters in intellectually disabled children suspected for IEMs were tested to see their association with intellectual disability, which could be helpful in preliminary screening. Methods: This comparative cross-sectional observational study was carried out from 2014 to 2017. Blood samples from 800 boys and girls (aged 4–24 years) were collected, of which 391 were healthy (IQ >90) and 409 were intellectually disabled (IQ <70) children with unknown cause. Clinically important (Liver and kidney enzymes etc.) biochemical parameters were analyzed in sera samples using commercial kits on semi-automated clinical chemistry analyzer. Results: Serum analysis showed the levels of ALP (p < 0.00001), ASAT (p = 0.001), ALAT (p = 0.016), albumin (p < 0.001), uric acid (p < 0.001), cholesterol (p < 0.001), triglycerides (p < 0.001), and hemoglobin (p = 0.005) were significantly different between healthy and intellectually disabled children. Conclusion: Changes in the liver function test and lipid profile parameters were significantly different in children with intellectual disability; however, it requires further detailed analysis for complete characterization of these diseases. [ABSTRACT FROM AUTHOR]

Background: To date, at least 746 genes have been identified to cause intellectual disability (ID). Among them, mutations in the Methyl CpG binding protein 2 (MECP2) gene are the leading cause of Rett syndrome and associated ID. Methods: Considering the large number of ID-associated genes, we applied trio-based whole-exome sequencing (trio-WES) and in silico analysis for genetic diagnosis of 294 children with ID. Results: Three de novo heterozygous mutations [NM_004992.3: c.502C > T, p.(Arg168*), c.916C > T, p.(Arg306Cys), and c.879C > G, p.(Ile293Met)] in MECP2 were identified in three unrelated girls. The first two mutations were detected in two patients who were diagnosed as typical Rett syndrome, X-linked ID and psychomotor retardation. The third mutation (c.879C > G), a previously unreported, was found in a 6-year-old girl with ID, microcephaly, severe underweight and psychomotor retardation. Particularly, this extremely rare de novo mutation (DNM) is located in the transcriptional repression domain (TRD) of MECP2, where at least 62 different causal mutations are identified. Conclusions: We identified three DNMs in MECP2 in a cohort of 294 individuals with ID. The novel c.879C > G mutation, as a likely pathogenic allele, may become a risk factor associated with X-linked ID, microcephaly and psychomotor retardation. [ABSTRACT FROM AUTHOR]

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Background: Intellectual disability (ID) constitutes the most common group of neurodevelopmental disorders. Exome sequencing has enabled the discovery of genetic mutations responsible for a wide range of ID disorders. Case presentation: In this study, we reported on two male siblings, aged 4 and 2 years, with motor and mental developmental delays and mild dysmorphic facial features. To identify the genetic causes of these symptoms, we employed trio-whole exome sequencing for the proband. We found a novel hemizygous missense variant in the PAK3 gene (c.1112G > A, p.Cys371Tyr), which encodes the p21-activated kinase 3, in the proband, which inherited from mother. The younger brother also has the hemizygous variant, which was confirmed by Sanger sequencing. The variant is located in the kinase domain and was regarded as a likely pathogenic variant in this family. Conclusion: We diagnosed two male siblings with developmental delays as having a PAK3 likely pathogenic variant. This finding expands the list of PAK3 gene mutations associated with neurodevelopmental disorders and provides further details on its clinical features. [ABSTRACT FROM AUTHOR]

Intellectual disability (ID) describes a wide range of serious human diseases caused by defects in central nervous system development and function. Some mutant genes have been found to be associated with these diseases, but not all cases can be explained, thus suggesting that other disease‐causing genes have not yet been discovered. Sialic acid is involved in a number of key biological processes, including embryo formation, nerve cell growth, and cancer cell metastasis, and very recently it has been suggested that N‐acetylneuraminic acid synthase‐mediated synthesis of sialic acid is required for brain and skeletal development. CMP‐sialic acid synthetase (CMAS) is one of four enzymes involved in NeuNAc metabolism, as it catalyzes the formation of CMP‐NeuNAc. Before the present study, no links between mutations in CMAS and incidences of human ID had been reported. In the current study, we recruited a recessive nonsyndromic ID pedigree with consanguineous marriage in which all patients have typical clinical manifestations of ID. We identified the NM_018686.3:c.563G > A (p.Arg188His) substitution in CMAS as being responsible for the disease in this family. Conservation analysis, structural prediction, and enzyme activity experiments demonstrated that (p.Arg188His) influences protein dimerization and alters CMAS enzyme activity. Our results offer a new orientation for future research and clinical diagnosis. [ABSTRACT FROM AUTHOR]

The Friendship Activity Scale and the Adjective Checklist were initially developed in the USA for the purpose of measuring children's attitudes towards intellectual disability (Siperstein, 1980). This research reports the development and validation of an Indonesian revision of these instruments, the Friendship Activity Observation Test (FAOT) and the Adjective Observational Checklistl (AOT) for use in its unified sports program (Special Olympics). Nine experts, with national and international level experience of 12-30 years, participated in this research. They comprised a psychometry expert, a sports psychology expert, a children with intellectual disability (ID) expert, a sport tests and measurements expert, and five unified sports trainers of children with ID. Content validity ratio (CVR) was used to assess the validity of the revised items. Following the formula proposed by Lawshe, the provision of a minimum value of CVR 0.78 was established as the criterion. Following the Delphi process, the average validity value of the items in each instrument was 0.945 for the FAOT and 0.941 for the AOT. The resulting drafts were then further tested and refined to check the content, construct, and rationale using the expert panel. The FAOT and AOT instruments when compared to the original versions were found to have increased utility in the Indonesian context as a result of increased balance in the number of indicators and items defining each factor, adjusting to the socio-cultural context of Indonesia, corresponding the instrument items and indicators to the context of unified sports for ID children, and the provision of implementation instructions, lattices instruments, as well as an observation-based rating rubric. [ABSTRACT FROM AUTHOR]

Abstract Background Autism spectrum disorder (ASD), a developmental disorder of early childhood onset, affects males four times more frequently than females, suggesting a role for the sex chromosomes. In this study, we describe a family with ASD in which a predicted pathogenic nonsense mutation in the X-chromosome gene RAB39B segregates with ASD phenotype. Methods Clinical phenotyping, microarray, and whole genome sequencing (WGS) were performed on the five members of this family. Maternal and female sibling X inactivation ratio was calculated, and phase was investigated. Mutant-induced pluripotent stem cells engineered for an exon 2 nonsense mutation were generated and differentiated into cortical neurons for expression and pathway analyses. Results Two males with an inherited RAB39B mutation both presented with macrocephaly, intellectual disability (ID), and ASD. Their female sibling with the same mutation presented with ID and a broad autism phenotype. In contrast, their transmitting mother has no neurodevelopmental diagnosis. Our investigation of phase indicated maternal preferential inactivation of the mutated allele, with no such bias observed in the female sibling. We offer the explanation that this bias in X inactivation may explain the absence of a neurocognitive phenotype in the mother. Our cellular knockout model of RAB39B revealed an impact on expression in differentiated neurons for several genes implicated in brain development and function, supported by our pathway enrichment analysis. Conclusions Penetrance for ASD is high among males but more variable among females with RAB39B mutations. A critical role for this gene in brain development and function is demonstrated.

Abstract Background Childhood disintegrative disorder (CDD) is a rare form of autism spectrum disorder (ASD) of unknown etiology. It is characterized by late-onset regression leading to significant intellectual disability (ID) and severe autism. Although there are phenotypic differences between CDD and other forms of ASD, it is unclear if there are neurobiological differences. Methods We pursued a multidisciplinary study of CDD (n = 17) and three comparison groups: low-functioning ASD (n = 12), high-functioning ASD (n = 50), and typically developing (n = 26) individuals. We performed whole-exome sequencing (WES), copy number variant (CNV), and gene expression analyses of CDD and, on subsets of each cohort, non-sedated functional magnetic resonance imaging (fMRI) while viewing socioemotional (faces) and non-socioemotional (houses) stimuli and eye tracking while viewing emotional faces. Results We observed potential differences between CDD and other forms of ASD. WES and CNV analyses identified one or more rare de novo, homozygous, and/or hemizygous (mother-to-son transmission on chrX) variants for most probands that were not shared by unaffected sibling controls. There were no clearly deleterious variants or highly recurrent candidate genes. Candidate genes that were found to be most conserved at variant position and most intolerant of variation, such as TRRAP, ZNF236, and KIAA2018, play a role or may be involved in transcription. Using the human BrainSpan transcriptome dataset, CDD candidate genes were found to be more highly expressed in non-neocortical regions than neocortical regions. This expression profile was similar to that of an independent cohort of ASD probands with regression. The non-neocortical regions overlapped with those identified by fMRI as abnormally hyperactive in response to viewing faces, such as the thalamus, cerebellum, caudate, and hippocampus. Eye-tracking analysis showed that, among individuals with ASD, subjects with CDD focused on eyes the most when shown pictures of faces. Conclusions Given that cohort sizes were limited by the rarity of CDD, and the challenges of conducting non-sedated fMRI and eye tracking in subjects with ASD and significant ID, this is an exploratory study designed to investigate the neurobiological features of CDD. In addition to reporting the first multimodal analysis of CDD, a combination of fMRI and eye-tracking analyses are being presented for the first time for low-functioning individuals with ASD. Our results suggest differences between CDD and other forms of ASD on the neurobiological as well as clinical level.

Assistive technologies are one of the five elements under the Health Component of the World Health Organization CBR Guidelines that Malawi is using to implement the Community Based Inclusive Development (CBID) Programme. The technologies enhance independent living by removing barriers that come due to disability or old age and should, therefore, be prioritized. However, Malawi does not have a straightforward way of providing Assistive Technology. Individuals are considered upon the assessment of their needs whose intervention with respect to assistive products may not be available. This is mostly the case with persons with intellectual disabilities, in which there is very little expertise to work with, in Malawi, although they require assistive products to improve their quality of life just like other persons with disabilities. There are many sectoral policies and laws in Malawi, nonetheless, they do not have a positive input on persons with intellectual disability to access assistive technologies in terms of availability (provision), affordability (cost), and appropriateness (suitability and quality). Therefore, this paper intends to demonstrate the barriers that are faced by persons with intellectual disabilities, examine the policies, and pieces of legislation that would have influenced better access and maps the way on how barriers can be removed to ensure that Assistive Technologies are readily and easily accessed.

The goal of this study is to present a comparative analysis between the three feature extraction techniques: Linear Predictive Coefficients (LPC), Linear Prediction Cepstral Coefficients (LPCC), and Weighted Linear Prediction Cepstral Coefficients (WLPCC) for distinguishing speech of Intellectually Disabled (ID) children from Typically Developed (TD). Speech samples of ID children were recorded from a government-owned special school in India and used for the analysis. Control samples were taken from the author's institute. Pre-processing techniques were used for better parameterization. Two classifiers, Artificial Neural Network (ANN) and Linear Discriminant Analysis , were applied to classify between disordered and the normal speech. Cross-validation technique was used to evaluate the reliability of the classifier. This study has discussed the effect on the classification accuracy using different values of frame size, percentage of frame overlapping, α value of pre-emphasis first-order filter and the order p. The experimental calculation interpreted that all the three parameterization techniques can be used for the correct classification of the ID speech from controls and WLPCC features slightly outperform than LPCC and considerably outperforms than LPC features. [ABSTRACT FROM AUTHOR]

X‐linked intellectual disability (XLID) refers to a clinically and genetically heterogeneous neurodevelopmental disorder, in which males are more heavily affected than females. Among the syndromic forms of XLID, identified by additional clinical signs as part of the disease spectrum, the association between XLID and severe myopia has been poorly characterized. We used whole exome sequencing (WES) to study two Italian male twins presenting impaired intellectual function and adaptive behavior, in association with severe myopia and mild facial dysmorphisms. WES analysis detected the novel, maternally inherited, mutation c.916G > C (G306R) in the X‐linked heparan sulfate 6‐O‐sulfotransferase 2 (HS6ST2) gene. HS6ST2 transfers sulfate from adenosine 3′‐phosphate, 5′‐phosphosulfate to the sixth position of the N‐sulphoglucosamine residue in heparan sulfate (HS) proteoglycans. Low HS sulfation levels are associated with defective optic disc and stalk morphogenesis during mammalian visual system development. The c.916G>C variant affects the HS6ST2 substrate binding site, and its effect was considered "deleterious" by in‐silico tools. An in‐vitro enzymatic assay showed that the HS6ST2 mutant isoform had significantly reduced sulphotransferase activity. Taken together, the results suggest that mutant HS6ST2 is possibly involved in the development of myopia and cognitive impairment, characteristics of the probands reported here. [ABSTRACT FROM AUTHOR]

Abstract The clinical significance of Xp22.31 microduplication is controversial as it is reported in subjects with developmental delay (DD), their unaffected relatives and unrelated controls. We performed multifaceted studies in a family of a boy with hypotonia, dysmorphic features and DD who carried a 600 Kb Xp22.31 microduplication (7515787-8123310bp, hg19) containing two genes, VCX and PNPLA4. The duplication was transmitted from his cognitively normal maternal grandfather. We found no evidence of the duplication causing the proband's DD and congenital anomalies based on unaltered expression of PNPLA4 in the proband and his mother in comparison to controls and preferential activation of the paternal chromosome X with Xp22.31 duplication in proband's mother. However, a de novo , previously reported deleterious, missense mutation in Pur-alpha gene (PURA) (5q31.2), with a role in neuronal differentiation was detected in the proband by exome sequencing. We propose that the variability in the phenotype in carriers of Xp22.31 microduplication can be due to a second and more deleterious genetic mutation in more severely affected carriers. Widespread use of whole genome next generation sequencing in families with Xp22.31 CNV could help identify such cases. [ABSTRACT FROM AUTHOR]

Abnormal gestational weight gain (GWG) has been increasing globally, up to 47% of all pregnancies. Multiple studies have focused on the association between GWG and adverse neurodevelopmental outcomes in the offspring, however with inconsistent results. We performed a systematic review and meta-analysis to evaluate associations between excessive or insufficient GWG and offspring's neurodevelopmental outcomes. Meta-analysis of these 23 studies using a random-effects model revealed associations between excessive GWG and neurodevelopmental disorders (ASD & ID & ADHD together: OR=1.12 [95% CI 1.06–1.19]), ASD (OR=1.18 [95% CI 1.08–1.29]), ADHD (OR=1.08 [95% CI 1.02–1.14]), ASD with ID (OR=1.15 [95% CI 1.01–1.32]), and ASD without ID (OR=1.12 [95% CI 1.06–1.19]). Insufficient GWG was associated with higher risk for ID (OR=1.14 [95% CI 1.03–1.26]). These results emphasize the significant impact, though of small effect size, of GWG across multiple neurodevelopmental disorders. It is important to note that these results do not establish causality. Other factors such as genetic factors, gene-environment interactions may confound the relationship between GWG and neurodevelopmental outcomes. To better understand the role of GWG in neurodevelopmental disorders, future studies should consider using genetically sensitive designs that can account for these potential confounders. • GWG above or below IOM guideline recommendations increases likelihood of offspring's neurodevelopmental disorders. • Young mothers and those of normal pre-pregnancy weight with excessive GWG in particular have a higher neurodevelopmental disorders likelihood in offspring. • The increased likelihood cuts across different neurodevelopmental disorders as autism and ADHD. [ABSTRACT FROM AUTHOR]

Introduction The living situation of individuals with intellectual disabilities (ID) has evolved throughout the years and ranges from living at home with family caregivers to group homes to independent living arrangements. Living situations can affect access to care and thus healthcare utilization seen by healthcare encounters for individuals with ID. Methods The researchers conducted a chart review of 112 patients to assess demographics, living situations, and healthcare encounters between 2019 and 2021. Living situation categories included independent, biological family, group home, home with other support, and others. Statistical analyses were conducted using R version 4.2.1 (The R Foundation for Statistical Computing, Vienna, Austria). Univariable analyses consisted of the Shapiro-Wilk test of normality, Kruskal-Wallis rank sum test, and pairwise Wilcoxon rank sum test with multiple comparisons correction using the Bonferroni method. Statistical testing for multivariable analysis included the Kruskal-Wallis rank sum test, Spearman's rank correlation, and the negative binomial model. Results Results showed a statistically significant difference in median total encounter value between independently living individuals with ID compared to all other living situations, Χ 2 = 4.230, df = 1, p-value = 0.040. Additionally, there is a significant association between medication count and total encounter count, rho = 0.341, S = 154322, p-value < 0.001. Conclusion The study showed that individuals with ID who live independently have fewer healthcare encounters compared to all other living situations. This may be due to various factors such as increased autonomy and free choice, increased barriers to healthcare, or better overall health requiring less medical attention in independently living individuals with ID., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Long et al.)

Résumé Contexte La prise en charge des troubles graves du comportement (TGC) des personnes avec autisme et déficience intellectuelle (DI) peut conduire à une surenchère de mesures d'isolement et de contention, voire de maltraitance. Dans ce contexte, nous proposons de colliger la littérature et les expériences pratiques, associées à l'utilisation d'équipements de protection individuelle (EPI) et d'outils de sécurisation alternatifs à la contention. Méthode Une revue exhaustive de la littérature a été conduite ainsi qu'une étude ethnographique de trois unités spécialisées dédiées, complétée par 37 interviews de professionnels soignants. Résultats Nous avons distingué les EPI pour les patients et les soignants. Au-delà de leur description, qui est corrélée à la topographie des blessures des patients et des soignants, que nous avons répertoriées, le modèle fonctionnel associé à leur utilisation permet d'appréhender en fonction de la cible clinique (automutilation, Pica, hétéro-agressivité) comment ces EPI peuvent contribuer à la restauration d'un raisonnement clinique utile à la prise en charge des TGC des personnes avec autisme et DI. Discussion Les EPI nous apparaissent un progrès d'un point de vue de l'analyse bénéfice/risque puisqu'ils permettent moins de blessures et moins de contraintes physiques. Ils permettent de rassurer les soignants qui peuvent alors mieux évaluer et réduire les TGC, et promouvoir des pratiques de sécurisation moins restrictive au sein de l'institution. Enfin, d'un point de vue éthique, ils contribuent à valoriser le meilleur intérêt de l'enfant et la reconnaissance du concept de vulnérabilité partagée. Abstract Context The management of severe behavioral disorders (SBD) in people with autism and intellectual disability (ID) can lead to an escalation of seclusion and restraints, even to abuse. In this context, we offer a literature review regarding the use of personal protective equipment (PPE), as well as the practical experiences associated with their use. Method An exhaustive review of the literature was conducted as well as an ethnographic study of three specialized units, supplemented by 37 interviews of healthcare professionals. Results We have distinguished between patients' PPEs and caregivers'. Their description is correlated with a detailed topography of patients' and caregivers' injuries. The functional model underpinning their use makes it possible to better capture, according to clinical targets (self-harm, Pica, hetero-aggression), how PPEs can contribute to the restoration of clinical reasoning useful for the management of SBDs among people with autism and ID. Discussion PPE appears to be a step forward from a risk-benefit point of view since it leads to fewer injuries and less physical constraints. They reassure caregivers who can better assess and reduce SBDs and foster less restrictive protective measures within the institution. Finally, from an ethical point of view, they contribute to promote the child's best interest and to recognize of the concept of shared vulnerability. [ABSTRACT FROM AUTHOR]

Résumé Contexte La prise en charge des troubles graves du comportement (TGC) des personnes avec autisme et déficience intellectuelle (DI) peut conduire à une surenchère de mesures d'isolement et de contention, voire de maltraitance. Dans ce contexte, nous proposons de colliger la littérature et les expériences pratiques, associées à l'utilisation d'équipements de protection individuelle (EPI) et d'outils de sécurisation alternatifs à la contention. Méthode Une revue exhaustive de la littérature a été conduite ainsi qu'une étude ethnographique de trois unités spécialisées dédiées, complétée par 37 interviews de professionnels soignants. Résultats Nous avons distingué les EPI pour les patients et les soignants. Au-delà de leur description, qui est corrélée à la topographie des blessures des patients et des soignants, que nous avons répertoriées, le modèle fonctionnel associé à leur utilisation permet d'appréhender en fonction de la cible clinique (automutilation, Pica, hétéro-agressivité) comment ces EPI peuvent contribuer à la restauration d'un raisonnement clinique utile à la prise en charge des TGC des personnes avec autisme et DI. Discussion Les EPI nous apparaissent un progrès d'un point de vue de l'analyse bénéfice/risque puisqu'ils permettent moins de blessures et moins de contraintes physiques. Ils permettent de rassurer les soignants qui peuvent alors mieux évaluer et réduire les TGC, et promouvoir des pratiques de sécurisation moins restrictive au sein de l'institution. Enfin, d'un point de vue éthique, ils contribuent à valoriser le meilleur intérêt de l'enfant et la reconnaissance du concept de vulnérabilité partagée. Abstract Context The management of severe behavioral disorders (SBD) in people with autism and intellectual disability (ID) can lead to an escalation of seclusion and restraints, even to abuse. In this context, we offer a literature review regarding the use of personal protective equipment (PPE), as well as the practical experiences associated with their use. Method An exhaustive review of the literature was conducted as well as an ethnographic study of three specialized units, supplemented by 37 interviews of healthcare professionals. Results We have distinguished between patients' PPEs and caregivers'. Their description is correlated with a detailed topography of patients' and caregivers' injuries. The functional model underpinning their use makes it possible to better capture, according to clinical targets (self-harm, Pica, hetero-aggression), how PPEs can contribute to the restoration of clinical reasoning useful for the management of SBDs among people with autism and ID. Discussion PPE appears to be a step forward from a risk-benefit point of view since it leads to fewer injuries and less physical constraints. They reassure caregivers who can better assess and reduce SBDs and foster less restrictive protective measures within the institution. Finally, from an ethical point of view, they contribute to promote the child's best interest and to recognize the concept of shared vulnerability. [ABSTRACT FROM AUTHOR]

A recent syndromic condition with craniofacial dysmorphisms, comprising congenital ocular defect and neurodevelopmental delay named Helsmoortel-Van der Aa Syndrome (HVDAS) (OMIM# 615873 ), has been described and molecularly defined, identifying pathogenic mutations in the ADNP gene (OMIM# 611386 ) as biological cause. We report on two children, displaying intellectual disability (ID) and peculiar congenital eyes anomalies, both carrying a de novo nonsense mutation in the ADNP gene. The review of present and literature reports, suggests that the diagnosis of HVDAS should be suspected in patients with ID accompanied by behavioral features in the Autism Spectrum Disorder and distinctive craniofacial phenotype. Among dysmorphisms due to malformation of the periorbital region, ptosis appears to be particularly recurrent in HVDAS. Furthermore, the present patients could support the inclusion of the HVDAS associated with specific mutations clustering within a small ADNP genomic region among clinical conditions reminiscent of the blepharophimosis/mental retardation syndromes (BMRS). [ABSTRACT FROM AUTHOR]

Deformed epidermal autoregulatory factor-1 (DEAF1), a transcription factor essential for central nervous system and early embryonic development, has recently been implicated in a series of intellectual disability-related neurodevelopmental anomalies termed, in this study, as DEAF1-associated neurodevelopmental disorder (DAND). We identified six potentially deleterious DEAF1 variants in a cohort of individuals with DAND via clinical exome sequencing (CES) and in silico analysis, including two novel de novo variants: missense variant c.634G > A p.Gly212Ser in the SAND domain and deletion variant c.913_915del p.Lys305del in the NLS domain, as well as c.676C > T p.Arg226Trp, c.700T > A p.Trp234Arg, c.737G > C p.Arg246Thr, and c.791A > C p.Gln264Pro. Luciferase reporter, immunofluorescence staining, and electrophoretic mobility shift assays revealed that these variants had decreased transcriptional repression activity at the DEAF1 promoter and reduced affinity to consensus DEAF1 DNA binding sequences. In addition, c.913_915del p.K305del localized primarily to the cytoplasm and interacted with wild-type DEAF1. Our results demonstrate that variants located within the SAND or NLS domains significantly reduce DEAF1 transcriptional regulatory activities and are thus, likely to contribute to the underlying clinical concerns in DAND patients. These findings illustrate the importance of experimental characterization of variants with uncertain significance identified by CES to assess their potential clinical significance and possible use in diagnosis. [ABSTRACT FROM AUTHOR]

Background: Autism spectrum disorder (ASD), a developmental disorder of early childhood onset, affects males four times more frequently than females, suggesting a role for the sex chromosomes. In this study, we describe a family with ASD in which a predicted pathogenic nonsense mutation in the X-chromosome gene RAB39B segregates with ASD phenotype. Methods: Clinical phenotyping, microarray, and whole genome sequencing (WGS) were performed on the five members of this family. Maternal and female sibling X inactivation ratio was calculated, and phase was investigated. Mutant-induced pluripotent stem cells engineered for an exon 2 nonsense mutation were generated and differentiated into cortical neurons for expression and pathway analyses. Results: Two males with an inherited RAB39B mutation both presented with macrocephaly, intellectual disability (ID), and ASD. Their female sibling with the same mutation presented with ID and a broad autism phenotype. In contrast, their transmitting mother has no neurodevelopmental diagnosis. Our investigation of phase indicated maternal preferential inactivation of the mutated allele, with no such bias observed in the female sibling. We offer the explanation that this bias in X inactivation may explain the absence of a neurocognitive phenotype in the mother. Our cellular knockout model of RAB39B revealed an impact on expression in differentiated neurons for several genes implicated in brain development and function, supported by our pathway enrichment analysis. Conclusions: Penetrance for ASD is high among males but more variable among females with RAB39B mutations. A critical role for this gene in brain development and function is demonstrated. [ABSTRACT FROM AUTHOR]